1. Technical Field
This disclosure relates generally to a nacelle for a turbofan engine and, more particularly, to a nacelle having a non-circular aft cowling geometry.
2. Background Information
Today, many aircraft are retrofitted to include modern turbofan propulsion systems that increase performance, while reducing costs. Such modern turbofan propulsion systems can include high or ultra-high bypass-ratio replacement turbofan engines designed to increase thrust, minimize weight and reduce noise levels and fuel consumption, and an aerodynamically streamlined nacelle. A typical high bypass engine includes a fan section, and an engine core. The nacelle includes a forward cowling disposed around the fan section, and a circular aft cowling disposed around the engine core.
Existing aircraft typically have a defined amount of space between the wing and the ground. Retrofit propulsion systems must fit within that defined amount of space without interfering with wing high-lift surfaces that articulate during operation or with access to the engine for routine maintenance. There is a need, therefore, for a nacelle that allows the installation of a high bypass-ratio turbofan engine, and one which does not interfere with articulation of wing high-lift surfaces. This is also true for the underwing installation of ultra-high bypass-ratio engines on all-new aircraft.